Ultrafast time-resolved interferometry at femtosecond laser excited surfaces

Summary form only given. Ultrashort pulsed laser ablation of absorbing solids exhibits unique, material-independent properties such as an extremely sharp threshold and ablation plumes with very steep fronts towards vacuum, leading to the observation of a characteristic transient interference phenomenon. To directly follow the expansion dynamics after femtosecond laser excitation we have developed an interferometric setup, which allows highly accurate measurements of transient surface deformations with a vertical sensitivity of <1 nm, a temporal resolution of 100 fs, and a lateral spatial resolution of 1-2 /spl mu/m. We schematically an imaging Michelson interferometer which is integrated into an optical pump-probe setup.